Vacuum cleaner robots are autonomous cleaning appliances which serve for automated cleaning of surfaces without having to be pushed or maneuvered by a user. Typically, the appliances are cordless to be able to navigate across an area to be cleaned, for example within a home, without difficulty and without the risk of a power cable getting tangled with furniture or other obstacles. The robot vacuum cleaner receives its power from rechargeable on-board batteries which may be recharged, possibly by the robot vacuum cleaner itself, at a charging station positioned within the home.
Due to the limited capacity of the rechargeable on-board batteries, the suction power of a suction fan motor of the robot vacuum cleaner is often lower than would be desirable for the cleaning process. For this purpose, robot vacuum cleaners of the above-mentioned type are provided with a rotating brush roller to assist the suction fan. The brush roller is disposed at the bottom of the housing of the robot vacuum cleaner, typically in the immediate vicinity of a suction opening of the robot vacuum cleaner. As the bristles of the brush roller rotate about a horizontal axle, they stir up dirt particles that have been caught, for example, in a carpet, making it easier for them to be sucked in and thus received by the suction opening of the robot vacuum cleaner.
One problem of such brush rollers is that threads and/or hairs may become wound around the brush roller as it rotates, as a result of which the bristles of the brush roller become clogged and contribute less effectively to the cleaning of the underlying surface. Wound-up hairs or threads could heretofore only be manually removed from the brush roller.
International Patent Publication WO 2013/060365 A1 describes a floor nozzle for a conventional vacuum cleaner, which floor nozzle has a rotating brush roller disposed therein. In order to clean the brush roller of hairs or threads, this floor nozzle has a blade which is disposed above the brush roller and which can be lowered onto the brush roller by operating a foot switch. The blade then cuts hairs and threads into smaller pieces while the brush roller is rotating and lifts them off the brush roller so that they can be sucked in.
However, the system and procedure described are not suitable for an autonomous robot vacuum cleaner, inter alia, because of the manual operation.